Object-Relational Spatial Indexing

In order to generate efficient execution plans for queries comprising spatial data types and predicates, the database system has to be equipped with appro­priate index structures, query processing methods, and optimization rules. Although available extensible indexing frameworks provide a gateway for seamless integration of spatial access methods into the standard process of query optimization and exe­cution, they do not facilitate the actual implementation of the spatial access method itself. An internal enhancement of the database kernel is usually not an option for database de­velopers. The embedding of a custom block-oriented index structure into concurrency control, recovery services and buffer management would cause extensive implemen­tation efforts and maintenance cost, at the risk of weakening the reliability of the entire system. The server stability can be preserved by delegating index operations to an ex­ternal process, but this approach induces severe performance bottlenecks due to con­text switches and inter-process communication. Therefore, we present the paradigm of object-relational spatial access methods that perfectly fits to the common relational data model and is highly compatible with the extensible indexing frameworks of ex­isting object-relational database systems allowing the user to define application-specific access methods.